Secrecy-switch for telephones



(Model) 8 8heets-$heet 1. E. T. GILLILAND.

Secrecy Switch for Telephones.

No. 241,963. Patented May 24,188l.

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E. T. GILLILAND. Secrecy Switch for Telephones. No. 241,963. PatentedMay 24, 1881,.

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I E. TQGILLILAND. Secrecy Switch for Telephones. 1N0. 241,963. rPatented May 24, L881.

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l PATENT EZRA T. GILLILAND, OF INDIANAPOLIS, INDIANA, ASSIGNOR TO THEAMERIOANBELL TELEPHONE COMPANY, OF BOSTON, MASSACHUSETTS.

SEGRECY-SWITC H. :FOR TELEPHON ES.

SPECIFICATION forming part of-Letters Patent No. 241,963, dated May 24,1881.

Application filed December 18, 1880-.- (ModeL) its position ischanged,-and in which the said change, when made, is also continuousuntil the position is changed again. This enables the user of anyinstrument (when it is on a line with other instruments) to be inconstant communication'wi'th the instruments in one of either of the twodirections from his own without impairing its usefulness for suchcommunication as may be desired with those in'the other direction. Theconvenience of such an .2 5 arrangement is illustrated by the case oftwo parties on the same line who are in almost constant communicationwith each other, and who but rarely have occasion to call the cen traloffice. The switch is then set so that tele- 0 phonic communication canordinarily be had between the parties exclusively, and only with thecentral oflice when the switch isturnediu the other direction. Whenthese conditions are reversed, and two parties are on one'line 3 5 whoordinarily have no occasion to communicute with each other, the switchis set so that the central office can only be communicated with unlessthe switch is changed.

Secrecy-switches, as heretofore constructed, while serving their primarypurpose of cutting out the instruments to one side while allowingcommunication with those on the other side, have, at the same time, alsocut the main line, and the position of the switch has, there'- 4 5 fore,always had to he changed as often'as the telephone was used. Whenevertheuser forgot to make this, change the line remained broken, and itsusefulness, untilthe mistake was corrected, has been thus destroyed.This disadvantage has been usually corrected by embodying in thesecrecy-switch the gravity-switch, and using the same as a support forthe telephone, but' in this use there has still remained thedisadvantage of being obliged to set the switch each time the telephonehas been used. 5 5

By'the peculiar construction of my improved switch and its connectionwith the ordinary gravity switch all these disadvantages are avoided andnew advantages are attained, as willpresently'be more particularly setforth.

For the sake of convenience in describing my improved" switch, and togive a clearer understanding of its operation, the instrument shown isto be considered an intermediate one ofa series'with the central office(or exchange) upon the right (other instruments may, of course, be alsoon the right, between this instrument and the central office) and one ormore other instruments upon the left, the last one of which is at theend of the line.

From the foregoing statements it will be seen that this invention is notintended for use, except where more than one instrument is on the line.

Referring to the accompanying drawings, which are made a part hereof,Figure 1 is a front elevation of an open bell-box; Fig. 2, a similarview, except that the magnetoengine isomitted, and the several sides ofthe box are swung apart so as to show all the connec- 8o tions, myimproved switch being attached to the inside of the cover, as in Fig. 1,but in a different position; Fig. 3, a front elevation of the'outside ofthe box, showing the bells and switch-handle; Fig. 4, a perspective viewof my improved switch and connections, as seen from the lower left hand,when in the position shown by Fig. 8; Fig. 5, a plan view of the lowersegments of the switch; Fig. 6, a plan view of the whole switch, insimilar position to that shown in Fig. 1, but on alarger scale; Figs. 7,8, and 9'plan views, similar to Fig. 6, except that the positionsof themovable segments arediiferent; Fig. 10, a section on the dotted-line m win Fig. 1, showing the parts 5 above'said line in elevation and Fig. 11,a section on the dotted. line y 3 in Fig. 1, showing the parts-to theleft of said line in elevation.

In said drawings, the portions marked A represent the various strips orwires which are connected with the main line leading toward the centraloiiice or instruments on the right, and are known as line-strips orconnections; B, the set of magnets used as the immediate mcans ofringing the bells, and being a portion of the device known as theringer; (J, the secrecy-switch which is the snbjectmattcr of thisinvention; D, the strips or wires connecting said switch with theinstruments on the left and leading through the magneto-engine; E, thestrips connecting the telephone to the other apparatus; 1,thc usualgravity-switch; G, a short strip which connects said gravityswitch tothesecrecy-switch, and forms a part of one or another electrical circuit,according to whether said switches are in one position or another; H, aspring-strip which forms a part of the main-line circuit, when thetelephone is cut out by reason of a weight being hung on thegravity-switch, but which terminates the line A, and consequently cutsout the ringer when the weight is removed from the gravity-switch, andsaid gravity-switch is brought into contact with the spring-strip E ofthe line E I, the magnetoen gine,by which the current is generated whichactuates the ringer in call-signaling; and J the groundwire of thetelephone.

The secrecy-switch U is composed of seg' ments 0 c 0 c fastenedpermanently to the cover of the box or other base on which the apparatusis mounted, two movable segments, 0 0, which are preferably in the formof springs, a cross-bar, c", to which the spring-segments are attached,and a shaft, c, which carries said cross-bar and movable segments, andis preferably operated by a suitable handle,C. The segments 0 c c c areseparated from each other by a suflicient space to prevent anyelectrical connection, and the cross-bar c is constructed of orseparated from the segments c c by hard rubber orother insulatingmaterial, so that said segments are also insulated from each other.

When all the parts are aranged as shown in Fig. 1 the telephone isintended for use in communicating with persons having instruments uponthe line running to the left, and the electric current, when theinstrument is in such use, takes the following course: Coming in overthe line D, itpasses through the mag neto-engine I, over the line D,through the permanent segment 0, movable segmen t c,permanentsegmentcflconnectiong,springG,aportion of the switch-barF,spring H, curl b coils B B, curl connection 1), segments 0 0 c, andout over the line A, causing the bell to ring in its passage intheordinary manner by its action on the magneto-coils B B. Itis obviousthat the call may come from the opposite direction, as while thegravityswitch F is in the position shown in this figure the current isfree to pass through the instrument in both directions, and will operateto ring the bell equally well while passing in one or the other. Thecall being received and the telephone taken down, the gravity-switch Fassumes the position shown in Fig. 2, and as the contact between saidswitch and the spring H is thereby broken the latter forms the terminusof the line A, cut ting out said line (and also the ringer) and makingthe conversation, so far as any instrument on said line A is concerned,entirely secret. A new contact is formed, however, between the switch Fand the spring E,forming a part of the telephone-connection and throwingthe telephone (which has previously been cut out) into the circuit andputting it in readiness for use.

When the secrecy-switch is in the position shown in Fig. 2 and thegravity-switch in the position shown in Fig. 1 the apparatus is arrangedfor communication with the central office or instruments to the rightover the line A, and the electrical current coming in over said line Awould pass through the segments 0 0 0 connection g, spring G,switch F,spring H, curl if, coils B B, curl b connection b, segments 0 c 0connections 1), engine I, and out over the line 1) as before, causingthe bell to ring in its passage. Of course, as in the previous case, acall from the other direction would pass through the instrument in there verse direction to that just described, but operating, as before, toring the hell. The call having been received and the telephone removedfrom the switch F, the latter assumes, as before, the position shown inthis figure, 2. The parting of the contact between the switch F and thespring H while the switch C is in this position has the effect ofcutting out the ringer and the magneto-engine, and of course destroyingall communication with the line D or instruments thereon, as said lineis only reached through said engine.

Should a call-signal be received from one direction when the apparatusis arranged for use in the other, the person answering has only to turnhis switch, by means of the handle C, and be prepared to hear thevoice-call made. In this case it is understood that a differentcall-signal is to be employed; but if, by mistake, it is not, the partycan first. listen a moment, and not hearing any voice-call, can thenturn the switch.

As will be readily understood from the foregoing desoription, when thesecrecy-switch U is in either of the positions shown in Figs. 1 and 2(also 6 and 7) and the gravity-switch F has the telephone hung thereon,the call-signal apparatus, both engineand ringer, is always in circuit,no matter from which direction the call comes. When the weight isremoved from the gravity-switch, (the secrecysvvitch beingstill in oneofthe positions named,) the telephoneis thrown into circuit, and thelineleading in one direction, and also the ringer, is cut out. When thesecrecy-switch is in the position shown by Figs. 1 and 6, the exchangeand instruments to the right are cut out, and the telephone is incommunication with the in- ICC struments to the left only. When thesecrecyswitch is in the position shown in Figs. 2 and 7 the exchange andinstruments to the right can be communicated with, and the instrumentsto theleft cannot be communicated with.

The positions already described comprise all that will usually beemployed, as the results do all ordinarily useful purposes. Otherpositions are shown, however, and will be now described, as occasionsmay arise when they will effect useful results.

When the secrecy-switch is in the position shown in Fig. 8, thetelephone and ringer are both out out, irrespective of the position ofthe gravity switch, and the instrument cannot therefore be used at all,but the line passes through unbroken. This can serve no useful purpose,save where the person having the instrument does not desire to have itused, or where it is out of order and it is desired to havecommunication between the instruments on each side while it is beingrepaired, or to secure it against damage by lightning during a storm.

The position shown by Fig. 9 is not one which it is expected that theswitch will ordinarily be placed in,as all communication is destroyed byso placing it, and the line rendered valueless for the time it is sopositioned.

To recapitulate: When the secrecy-switch is in the position shown inFig. 1, the call-signal can be made from either direction, and by meansof the operation of the gravity-switch the telephone can be used tocommunicate with instruments on the left. When the secrecyswitch is inthe position shown in Fig. 2, the call-signal can be made as before, butthe telephone can only be used to communicate with instruments on theright. When the secrecyswitch is in position as shown in Fig. 8, nocall-signal or telephonic communication can be held, but the line forotherinstruments remains unbroken. When the secrecy-switch is inposition as shown in Fig. 9, the line is broken for all instrumentsthereon, as well as for the one in which the switch is located, so faras communication past said instrument is concerned. 7

It will be understood, of course, that the describing ot' the centraloflice as being located to the right, and the end of the line as to theleft in this specification, is simply for convenience in describing theoperation of the invention, and that in practice these locations may bereversed. It will also be understood that the exact location andarrangement of the several parts and connections shown is not essentialto the operation of my invention, but that these matters, as well as theform of construction, may be varied considerably without departing fromsaid invention.

Having thus fully described my said invention, what I claim as new, anddesire to secure by Letters Patent, is-

1. The combination of a secrecy-switch, an independent telephone-switchand their contacts, and electrical connections, substantially asdescribed, so that the two sections of a linewire can be connected witheach other, or either of them grounded through the telephone, accordingto the position of the switches, as set forth.

2. A secrecy-switch for telephone-lines, comprising segments insulatedfrom each other, line-strips or conductors connected with a pair of saidsegments, local strips through which connection is made between theline-strips and between one or the other and the telephonic instruments,and other segments suitably mounted and movable over the first-namedsegments, the said segments and conductingstrips being arrangedsubstantially as described, so that either of the line-strips can beconnected with either of the local strips thron gh the aforesaidsegments, as set forth.

3. The combination of a secrecy-switch comprising fixed and movablesegments, as specified, with a gravity-switch, its contact-points,conductors connected with said points, and a conductor connecting thetwo switches with each other, substantially as described.

4. In atelephone apparatus, the combination, with a secrecy-switch, of agravity-switch having an electrical connection therewith, which is atall times in operation, and a connection with the ringer and one withthe telephone, of

which only one shall be in operation at any one time, substantially asset forth.

5. The combination, with a secrecy-switch and a gravity-switchconstructed independently of each other, of a strip, G, which forms aconnection between said two switches regardless of the positionsoccupied thereby, substantially as set forth.

In witness whereof I have hereunto set my hand and seal at Indianapolis,Indiana, this 11th day of December, A. D. 1880.

EZRA T. GILLILAND.

